Number of rules of a context-free grammar in Chomsky normal form that generates all permutations of n symbols.

A090327

Number of rules of a context-free grammar in Chomsky normal form that generates all permutations of n symbols.

Terms

    a(0) =1a(1) =4a(2) =11a(3) =30a(4) =83a(5) =234a(6) =671a(7) =1950a(8) =5723a(9) =16914a(10) =50231a(11) =149670a(12) =446963a(13) =1336794a(14) =4002191a(15) =11990190a(16) =35937803a(17) =107747874a(18) =323112551a(19) =969075510a(20) =2906702243a(21) =8719058154a(22) =26155077311a(23) =78461037630a(24) =235374724283a(25) =706107395634

External references